Method of catalysis



Feb. s, 1949.

J. R. BATESV METHOD 0F CATALYSIS Filed Sept. 14, 1945 INVENTOR.

Patented Feb. 8, 1949 METHOD F CATALYSIS John a. Bam, Swarthmore; ra., minor it sch Oil Company, Philadelphia, Pa., a corporation of New Jersey Application September 14, 1945, Serial No. 316,169

l 3 Claims. l

The present invention relates to a method of catalysis in which reactant vapors. are contacted with a granular catalyst and in which the catalyst is subject to considerable mechanical handling. In such processes the handling or movement of the catalyst results in a considerable degradation in particle size of the catalyst and a substantial amount of the catalyst is frequently ground into ne dust which is not only of little or no value as a catalyst but is picked up by the reactant vapors and is removed from the conversion zone suspended or entrained in the reactant vapors and is therefore lost. The attrition losses of the catalyst in moving catalyst `units are frequently so high that only relatively inexpensive materials may be employed as catalysts in such operations. An example of this is the catalytic conversion of hydrocarbons. In moving catalyst units employed for the conversion of hydrocarbons it has been found that the attrition losses are so high that the only catalyst which may be economically employed is a clay type catalyst. Other catalysts, particularly certain syn. thetio catalysts, which are frequently more eiective for particular applications, areso expensive that the relatively large loss of such catalysts as fines in such moving catalyst units `makes their. use economically iriadvi-sable.v Efforts have been made to reduce the attrition loss of catalysts in moving catalyst units, but these efforts have generally been directed toward ilnding relatively losses have met with some success, they result in f a substantial increase in the initial cost of the catalyst and do, not completely prevent attrition losses.

The present process is directed to amethod of handling the catalyst so that attrition losses are substantially reduced. The method embodied the present invention is applicable to moving catalyst units employing either a relatively low; cost clay type ycatalyst or more expensive synthetic catalysts. It is also applicable to catalysts ,which are specially processed so as to have relatively low attrition losses. 4

In order to vfully describe the presentinvention there is attached hereto a sheet of `clraviriiis the single gure of which is a diagrammatic illustration of a moving catalyst unit adapted to employ the features of the presentinvention. Reference bed of catalyst is maintained in converter I and used catalyst may be continuously withdrawn from the bottom of converter I through .star valve 3 at the same rate `at which fresh catalyst is supplied to converter I through inlet 2. The catalyst removed from converter I through star valve 3 drops into purge chamber 4 wherein a bed of catalyst is maintained and from which the purged catalyst is withdrawn at a rate equivalent to that at which used catalyst is introduced thereinto, through star valve 5. From star valve `5 the purged catalyst falls into regenerating chamber 6 within which a bed of catalyst undergoing regeneration is maintained and from the bottom of which regenerated catalyst is withdrawn through star valve .1. `From star valve 1 the regenerated catalyst falls into purge chamber 8, wherein the catalyst is purged and from the bottom of the purge chamber catalyst is removed In the operation of theforegoing diagrammatically illustrated apparatus'the reactant vapors to be converted are l.introduced through line v I3 into the bed of catalysts in converter I'at a point near the bottom thereof. The reactant vapors rise through the bed ofcatalysts and are 4removed from converter I through outlet linel I4 after having undergone the` desired chemical conversion. During.y thevpassage of vapors through kconverter I they may pick up a certain amount of fines and these willbepremoved along with the yreacted vapors through line I4. Inorder to recover` these ilnes the vapors'flowing through line Il may enter a fsuitable; dust separator,y for instance a cyclone separator I5. from which the vapors free of any entrained ilnes are removed throughline I6 while the separated ilnes maybe wfremoved; through line I1 and ilow or be conveyed to line I8. In purge chamber 4 a suitable purging huid, for instance superheated steamer some other inert gas. may be passed through the. bed of used catalyst contained therein, the purge iluid being introduced through line i9. rising 4through 1 3 thebedofcatalystand chamber I through line 2l together with any reactant vapors present in the used catalyst. The

purge iluid and reactant vapors contained therein may ilow to a cyclone separator 2I from which the purge iluid is removed through line 22 and any catalyst lines entrained in the fluids are removed through line 23 and ilow to line Il. In regenerator 6 a suitable regenerating medium, for instance air to burn oil any carbonaceous deposits on catalyst in case hydrocarbon fluids are being treated in converter I, is'introduced into the bed of catalysts maintained'therein through line 2l at a point near the bottom of the bed of catalyst.

The regenerating medium rises through the bed of catalyst in regenerator I and is removed therefrom through line 25 and ows to cyclone separator 26, the products of regeneration being removed therefrom through line 21 while any catalyst ilnes removed therefrom through line 2l ilow to line I l. In purge chamber l any suitable purging fluid, for instance steam or other inert gas, is introduced in the bed of catalysts maintained therein through line 29, passes through o the bed of catalysts and is removed from purge chamber 8 through line III together with any oxidizing gas or other regenerating medium which may be entrained in the catalyst. The used purge bcingrcmovediromwrle gas passes through line to cyclone separator l I, the gaseous portion thereof is removed through line 32 and any catalyst iines are removed through line 32 and ow to line Il.`

' I have discovered that if a small but appreci`v able quantity of fines not larger than will pass quirewhat may be considered a coating thereon 4 will for most operationsbegrcater than the quantity required to cilect the lubrication. the

^ excess of selected nues may be removed from the apparatus'through valved outlet 4I and only the required small-percentage returned to the apparatus.

It will be understood that to the extent that reduction of attrition approaches the absolute. to that.l extent removal of powdered lines from the endless catalyst stream is unnecessary, since there could be `no progressive accumulation of powdered nes. Since, however, my process does not necessarilycontemplate absolute prevention of attrition, but only its reduction to a minimum, separation from the moving catalyst mass of some proportion of the powdered fines is necessary. Such separation, however, need not be continuous, since an increase in the proportion of powdered fines within the range .05 to .5 or 1% is permissible; and partial separation of powdered fines from the endless catalytic stream is necessary only when. from time to time, the progressive, but exceedingly slow, increase in. the

percentage v of 4powdered iinesfexceeds or 'approaches the maximum permissible percentage of powderedfnes'in the endless catalyst stream above which further substantial attrition could not be prevented'.

This application is la continuation-impart of.

my application `led October 23, 463,040, now abandoned.

What I claim and desire to protect by Letters Patentis:

" 1. In a catalytic operation in which fluids are 1942, Serial No.

contacted with a ,mass of' catalyst of solid particles which movesf continuously in anendless 40 of a degree of iineness greatly exceeding that of which prevents a grinding action of the particlesl with each other and hence the attrition is reduced substantially. All 'of 4the ilnes formed in the apparatus during its operation are directed from line I8 into 'a vibratcry screen separator 38 from which a desired quantity of those that are not larger than 150 or 200 mesh are returned to the body of owing catalyst preferably as indi-- cated adjacent the inlet of conveyor 'I0 through valved line 39; The/fines largerthan150 mesh u `j i are not employed in the process `and these may be Y f lremoved from separator 2l through the line Il.

By returning` a predetermined small percent- Y age o! the selected nes to thecatalyst at ,this

point in the 'apparatus proper lubricating action apparatus and hence'v more beneilcial results are any selected point. For example, thenes from separators I5, 2| 26 and 3l may be further separated and those not larger than 150 or 200 vmesh returned to the apparatus at any selected point.v

' Only a very small f percentage of the selected nnes are needed to vreii'cct a' lubrication of the catalyst particles. The amount o f the selected particles to be returned to the lconveyer I l to b y thegiines is provided for all particles of the catalyst during'their passasethroushthe entire Vwhich rines' leaveithetreatingf zone entra-inedyin escapingffiluids, .Ythemethodvof minimizing such. f attritionlwhich :comprises vremoving the ilnes the particles of the moving catalyst mass. and in which lines leave the treating z'oneentrained in escaping-fluids, the'method vof minimizing such attrition. which comprises removing thev lines from the escaped iiuids, separating 4from the removed flnesthose'which" are larger than 150 mesh and returning a small percentage of the remain-. ing nes 'to theimoving catalyst mass in orderj to lub'ric'za'te"` the. massf and thereby minimize u attrition.-Y

291x138' catnytic operation inwni'cn uuidsfaltrc` contacted with 'a'k mass of catalyst' of; `so1id "particleswhich-k moves continuously. in an endless s'treamin'to," through, out of, and back to a treat the particles ofiithe'mov'ing'catalyst mass and in from the escapediluida 4separating'irom the refmoved fines thosewhich are larger than mesh tain thereonaprdetermined percentage thereof provide e'ective lubrication has beenfou'nd to `be I lected lubricating lines collected in the separator less than one per cent and generally the amount f will be of the order oi' .05 to..5 per cent by weight of the catalyst. Since the quantityof the vse' mg'fzon einem wvaicjtneparticies are subjected lngz'one and inf whlchthe particles are subjectedv d tofmechanicalf attritionforming powieredi-ilues l 1 of a'degrjee ofinen'essgreatly exceeding' that'ofi 1 ...operation unich naiss4 are '1o coqtacted-1withia-massf of catalyst of, sono i 'zticles which m'OveS 'f'wnuslr man endless screenname: th'rcu'gueu bffandbaekto, a treat.

vMemo@ the particles of the moving catalyst massand in which nes leave the treating zone entrained in escaping fluids, the method of minimizing such attrition which comprises removing the nes from the escaped fluids, separating from the removed fines those which are larger than 150 mesh and returning to the moving catalyst mass such percentage of the remaining nes as will continuously maintain between .05 and 1 per cent byl weight of such nes in such mass.

' JOHN R. BATES.

' REFERENCES CITED UNITED STATES PATENTS Number Name Date Simpson et al Oct. 12, 1943 

